Lead-acid batteries, which exist over hundred years and have a mature technology, have accumulated dominant market share in car starting batteries, electric bicycles, UPS and other energy storage areas. Although the cycle life and the energy density are relatively low, lead-acid batteries characterize high cost effectiveness. Thus, in recent years lead-acid batteries cannot be replaced by nickel-metal hydride batteries, lithium ion batteries and sodium sulfur batteries in energy storage area.
A new ion exchange battery comprises a cathode, an anode and en electrolyte, the working principle could be summarized as follows: during the charging process, the first metal ions deintercalate from the cathode, while simultaneously, the second metal ions in the electrolyte are reduced and deposited onto the surface of the anode. Theoretical energy density of the ion exchange battery is 160 Wh/Kg, and the actual energy density is expected to reach 50˜80 Wh/Kg. Therefore this type of battery could be a promising alternative of lead-acid batteries in next generation storage batteries.
However, the electrolytes used in the ion exchange battery are acetate, hydrochloride, and sulfate. Acetate could be easily oxidized due to its poor stability, which results in great self-discharge; Cathode current collector could be corroded in hydrochloride solution; and the corrosion of anode in sulfate cannot be ignored.